1 /* rename.c -- rename a file, preserving symlinks.
2 Copyright (C) 1999-2020 Free Software Foundation, Inc.
3
4 This file is part of GNU Binutils.
5
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
10
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
19 02110-1301, USA. */
20
21 #include "sysdep.h"
22 #include "bfd.h"
23 #include "bucomm.h"
24
25 #ifdef HAVE_GOOD_UTIME_H
26 #include <utime.h>
27 #else /* ! HAVE_GOOD_UTIME_H */
28 #ifdef HAVE_UTIMES
29 #include <sys/time.h>
30 #endif /* HAVE_UTIMES */
31 #endif /* ! HAVE_GOOD_UTIME_H */
32
33 #if ! defined (_WIN32) || defined (__CYGWIN32__)
34 static int simple_copy (const char *, const char *);
35
36 /* The number of bytes to copy at once. */
37 #define COPY_BUF 8192
38
39 /* Copy file FROM to file TO, performing no translations.
40 Return 0 if ok, -1 if error. */
41
42 static int
simple_copy(const char * from,const char * to)43 simple_copy (const char *from, const char *to)
44 {
45 int fromfd, tofd, nread;
46 int saved;
47 char buf[COPY_BUF];
48
49 fromfd = open (from, O_RDONLY | O_BINARY);
50 if (fromfd < 0)
51 return -1;
52 #ifdef O_CREAT
53 tofd = open (to, O_CREAT | O_WRONLY | O_TRUNC | O_BINARY, 0777);
54 #else
55 tofd = creat (to, 0777);
56 #endif
57 if (tofd < 0)
58 {
59 saved = errno;
60 close (fromfd);
61 errno = saved;
62 return -1;
63 }
64 while ((nread = read (fromfd, buf, sizeof buf)) > 0)
65 {
66 if (write (tofd, buf, nread) != nread)
67 {
68 saved = errno;
69 close (fromfd);
70 close (tofd);
71 errno = saved;
72 return -1;
73 }
74 }
75 saved = errno;
76 close (fromfd);
77 close (tofd);
78 if (nread < 0)
79 {
80 errno = saved;
81 return -1;
82 }
83 return 0;
84 }
85 #endif /* __CYGWIN32__ or not _WIN32 */
86
87 /* Set the times of the file DESTINATION to be the same as those in
88 STATBUF. */
89
90 void
set_times(const char * destination,const struct stat * statbuf)91 set_times (const char *destination, const struct stat *statbuf)
92 {
93 int result;
94
95 {
96 #ifdef HAVE_GOOD_UTIME_H
97 struct utimbuf tb;
98
99 tb.actime = statbuf->st_atime;
100 tb.modtime = statbuf->st_mtime;
101 result = utime (destination, &tb);
102 #else /* ! HAVE_GOOD_UTIME_H */
103 #ifndef HAVE_UTIMES
104 long tb[2];
105
106 tb[0] = statbuf->st_atime;
107 tb[1] = statbuf->st_mtime;
108 result = utime (destination, tb);
109 #else /* HAVE_UTIMES */
110 struct timeval tv[2];
111
112 tv[0].tv_sec = statbuf->st_atime;
113 tv[0].tv_usec = 0;
114 tv[1].tv_sec = statbuf->st_mtime;
115 tv[1].tv_usec = 0;
116 result = utimes (destination, tv);
117 #endif /* HAVE_UTIMES */
118 #endif /* ! HAVE_GOOD_UTIME_H */
119 }
120
121 if (result != 0)
122 non_fatal (_("%s: cannot set time: %s"), destination, strerror (errno));
123 }
124
125 #ifndef S_ISLNK
126 #ifdef S_IFLNK
127 #define S_ISLNK(m) (((m) & S_IFMT) == S_IFLNK)
128 #else
129 #define S_ISLNK(m) 0
130 #define lstat stat
131 #endif
132 #endif
133
134 /* Rename FROM to TO, copying if TO is a link.
135 Return 0 if ok, -1 if error. */
136
137 int
smart_rename(const char * from,const char * to,int preserve_dates ATTRIBUTE_UNUSED)138 smart_rename (const char *from, const char *to, int preserve_dates ATTRIBUTE_UNUSED)
139 {
140 bfd_boolean exists;
141 struct stat s;
142 int ret = 0;
143
144 exists = lstat (to, &s) == 0;
145
146 #if defined (_WIN32) && !defined (__CYGWIN32__)
147 /* Win32, unlike unix, will not erase `to' in `rename(from, to)' but
148 fail instead. Also, chown is not present. */
149
150 if (exists)
151 remove (to);
152
153 ret = rename (from, to);
154 if (ret != 0)
155 {
156 /* We have to clean up here. */
157 non_fatal (_("unable to rename '%s'; reason: %s"), to, strerror (errno));
158 unlink (from);
159 }
160 #else
161 /* Use rename only if TO is not a symbolic link and has
162 only one hard link, and we have permission to write to it. */
163 if (! exists
164 || (!S_ISLNK (s.st_mode)
165 && S_ISREG (s.st_mode)
166 && (s.st_mode & S_IWUSR)
167 && s.st_nlink == 1)
168 )
169 {
170 ret = rename (from, to);
171 if (ret == 0)
172 {
173 if (exists)
174 {
175 /* Try to preserve the permission bits and ownership of
176 TO. First get the mode right except for the setuid
177 bit. Then change the ownership. Then fix the setuid
178 bit. We do the chmod before the chown because if the
179 chown succeeds, and we are a normal user, we won't be
180 able to do the chmod afterward. We don't bother to
181 fix the setuid bit first because that might introduce
182 a fleeting security problem, and because the chown
183 will clear the setuid bit anyhow. We only fix the
184 setuid bit if the chown succeeds, because we don't
185 want to introduce an unexpected setuid file owned by
186 the user running objcopy. */
187 chmod (to, s.st_mode & 0777);
188 if (chown (to, s.st_uid, s.st_gid) >= 0)
189 chmod (to, s.st_mode & 07777);
190 }
191 }
192 else
193 {
194 /* We have to clean up here. */
195 non_fatal (_("unable to rename '%s'; reason: %s"), to, strerror (errno));
196 unlink (from);
197 }
198 }
199 else
200 {
201 ret = simple_copy (from, to);
202 if (ret != 0)
203 non_fatal (_("unable to copy file '%s'; reason: %s"), to, strerror (errno));
204
205 if (preserve_dates)
206 set_times (to, &s);
207 unlink (from);
208 }
209 #endif /* _WIN32 && !__CYGWIN32__ */
210
211 return ret;
212 }
213